When soldiers discuss their experiences at war, they often talk of a breaking point — the first time they pulled the trigger, saw a friend get killed, or killed someone themselves. Regardless of the circumstance, it is the moment they realized that the events around them were real and would change them forever.

Readers of Kevin Sites' “The Things They Cannot Say: Stories Soldiers Won't Tell You About What They've Seen, Done or Failed to Do in War” will have a similar experience, one that, while perhaps not life-altering, instantly convinces them that this subject is a good deal more important than most. This was my breaking point:

“A piece of brain matter fell from the head of one of the insurgents and a Marine used a piece of wood to scoot it across the floor, back toward its owner.”

The line comes early and is only an aside, which says a lot about the book's purpose: to look directly at the violence of war — the grim, dirty business of killing others, asking not only how soldiers do it, but how they handle it, if, that is, they can handle it. You know you're in trouble when brain matter is just the beginning.

It is hard and slippery terrain — and one that Sites knows well. As a war correspondent for several major networks, he is best known for releasing controversial footage of a Marine killing a wounded and unarmed insurgent in a Fallujah mosque.

He is haunted, however, by another incident, one that triggered years of post-traumatic stress, not to mention alcohol and drug abuse. “I walked away ... from a man very much alive and pleading with me to help him. ... To this day, I can't begin to fathom how I could have been so stupid.” The man, an insurgent, was injured and unarmed and brutally murdered shortly afterward.

Throughout the book, Sites movingly discusses his guilt over this one careless action, although his primary focus is on soldiers and Marines themselves. He profiles 11 of them on a range of experiences, including what it feels like to kill both enemies and colleagues; to lose a friend who was covering your position; to forget how to love, even your own daughter; and, finally, what it's like to be the one leading young men into battle.

For if there is one thing binding his subjects, it is their youth — many of them signed up for service while still in high school, eager to serve their country and escape it at the same time. They often came from poor or neglectful families. When they arrive at their destination, they are scared and anxious.

“When I first got here,” confesses William Wold, who joined the Marines at 17, “I was always worried about getting killed. ... But now, I don't have time to think about that (expletive) ... Just like today, I had people pointing AKs at me. And I was thinkin', 'I have to shoot them.' I shot six people in less than ten seconds. It's just what you've got to do.”

As you read on, you realize that soldiers endure two wars — the fast one, described here, but also a slower, equally grueling one in which they go back home and think about what they did.